Method of improving interlayer adhesion

ABSTRACT

Methods are provided for processing a substrate for depositing an adhesion layer having a low dielectric constant between two low k dielectric layers. In one aspect, the invention provides a method for processing a substrate including depositing a barrier layer on the substrate, wherein the barrier layer comprises silicon and carbon and has a dielectric constant less than 4, depositing a dielectric initiation layer adjacent the barrier layer, and depositing a first dielectric layer adjacent the dielectric initiation layer, wherein the dielectric layer comprises silicon, oxygen, and carbon and has a dielectric constant of about 3 or less.

BACKGROUND OF THE DISCLOSURE

[0001] 1. Field of the Invention

[0002] The invention relates to the fabrication of integrated circuitsand to a process for depositing dielectric layers on a substrate and thestructures formed by the dielectric layer.

[0003] 2. Description of the Related Art

[0004] One of the primary steps in the fabrication of modernsemiconductor devices is the formation of metal and dielectric layers ona substrate by chemical reaction of gases. Such deposition processes arereferred to as chemical vapor deposition or CVD. Conventional thermalCVD processes supply reactive gases to the substrate surface whereheat-induced chemical reactions take place to produce a desired layer.

[0005] Semiconductor device geometries have dramatically decreased insize since such devices were first introduced several decades ago. Sincethen, integrated circuits have generally followed the two year/half-sizerule (often called Moore's Law), which means that the number of devicesthat will fit on a chip doubles every two years. Today's fabricationplants are routinely producing devices having 0.35 μm and even 0.18 μmfeature sizes, and tomorrow's plants soon will be producing deviceshaving even smaller geometries.

[0006] To further reduce the size of devices on integrated circuits, ithas become necessary to use conductive materials having low resistivityand to use insulators having low dielectric constants (dielectricconstant<4.0) to also reduce the capacitive coupling between adjacentmetal lines. One such low k material is spin-on glass, such as un-dopedsilicon glass (USG) or fluorine-doped silicon glass (FSG), which can bedeposited as a gap fill layer in a semiconductor manufacturing processand silicon oxycarbide which can used as a dielectric layer infabricating damascene features.

[0007] One conductive material gaining acceptance is copper and itsalloys, which have become the materials of choice for sub-quarter-microninterconnect technology because copper has a lower resistivity thanaluminum, (1.7 μΩ-cm compared to 3.1 μΩ-cm for aluminum), a highercurrent and higher carrying capacity. These characteristics areimportant for supporting the higher current densities experienced athigh levels of integration and increased device speed. Further, copperhas good thermal conductivity and is available in a very pure state.

[0008] One difficulty in using copper in semiconductor devices is thatcopper is difficult to etch and achieve a precise pattern. Etching withcopper using traditional deposition/etch processes for forminginterconnects has been less than satisfactory. Therefore, new methods ofmanufacturing interconnects having copper containing materials and low kdielectric materials are being developed.

[0009] One method for forming vertical and horizontal interconnects isby a damascene or dual damascene method. In the damascene method, one ormore dielectric materials, such as the low k dielectric materials, aredeposited and pattern etched to form the vertical interconnects, i.e.vias, and horizontal interconnects, i.e., lines. Conductive materials,such as copper containing materials, and other materials, such asbarrier layer materials used to prevent diffusion of, copper containingmaterials into the surrounding low k dielectric, are then inlaid intothe etched pattern. Any excess copper containing materials and excessbarrier layer material external to the etched pattern, such as on thefield of the substrate, is then removed.

[0010] However, when silicon oxycarbide layers and silicon carbidelayers are used as the low k material in damascene formation, less thansatisfactory interlayer adhesion has been observed during processing.Some techniques for processing substrates may apply forces that canincrease layering defects, such as layer delamination. For example,excess copper containing materials may be removed by mechanical abrasionbetween a substrate and a polishing pad in a chemical mechanicalpolishing process, and the force between the substrate and the polishingpad may induce stresses in the deposited low k dielectric materials toresult in layer delamination. In another example, annealing of depositedmaterials may induce high thermal stresses that can also lead todelamination in low k dielectric materials.

[0011] Therefore, there remains a need for a process for improvinginterlayer adhesion between low k dielectric layers.

SUMMARY OF THE INVENTION

[0012] Aspects of the invention generally provide a method fordepositing an adhesion layer having a low dielectric constant betweentwo low k dielectric layers. In one aspect, the invention provides amethod for processing a substrate including depositing a barrier layeron the substrate, wherein the barrier layer comprises silicon and carbonand has a dielectric constant less than 4, depositing a dielectricinitiation layer adjacent the barrier layer, and depositing a firstdielectric layer adjacent the dielectric initiation layer, wherein thedielectric layer comprises silicon, oxygen, and carbon and has adielectric constant of about 3 or less.

[0013] In another aspect of the invention, a method is provided forprocessing a substrate including depositing a first dielectric layer onthe substrate, wherein the first dielectric layer comprises silicon andcarbon and is deposited by a process comprising introducing a processinggas having an organosilicon compound and reacting the processing gas todeposit the first dielectric layer, reducing the carbon content at asurface portion of the first dielectric layer, and then depositing asecond dielectric layer adjacent the first dielectric layer, wherein thefirst dielectric layer comprises silicon, oxygen, and carbon and has adielectric constant of about 3 or less.

[0014] In another aspect of the invention, a method is provided forprocessing a substrate including depositing a barrier layer on thesubstrate, wherein the barrier layer is deposited by introducing aprocessing gas comprising an organosilicon compound into a processingchamber and reacting the processing gas, depositing a barrier layertermination layer adjacent the barrier layer, wherein the barrier layeris deposited by introducing a processing gas comprising an organosiliconcompound and an oxidizing compound into a processing chamber andreacting the processing gas, and depositing a first dielectric layeradjacent the barrier layer termination layer, wherein the dielectriclayer comprises silicon, oxygen, and carbon and has a dielectricconstant of about 3 or less.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] So that the manner in which the above aspects of the inventionare attained and can be understood in detail, a more particulardescription of the invention, briefly summarized above, may be had byreference to the embodiments thereof which are illustrated in theappended drawings.

[0016] It is to be noted, however, that the appended drawings illustrateonly typical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

[0017]FIG. 1 is a cross-sectional view showing a dual damascenestructure comprising the silicon carbide and silicon oxycarbide layersdescribed herein; and

[0018]FIGS. 2A-2H are cross-sectional views showing one embodiment of adual damascene deposition sequence of the invention.

[0019] For a further understanding of aspect of the invention, referenceshould be made to the ensuing detailed description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Aspects of the invention described herein refer to a method andapparatus for depositing an adhesive dielectric material and/or treatingthe surface between dielectric layers to improve interlayer adhesion ofdielectric layers. Deposition of an adhesive dielectric layer maycomprise forming a termination layer on a first dielectric layer orforming a dielectric initiation layer before depositing a subsequentdielectric layer. The adhesive dielectric material may comprise silicon,carbon, and optionally, oxygen. Treatments to improve adhesion betweenthe dielectric layers include modifying the surface of a deposited layerprior to subsequent deposition, for example, the application of oxidizedplasma treatment between dielectric layer depositions. Treating of thesurface of a silicon, carbon, and optionally, oxygen containing materialis believed to reduce the carbon content from the deposited material tothereby improve interlayer adhesion. While the following description isdirected to improving the adhesion between the silicon carbide layersand the silicon oxycarbide layer, the following examples and descriptionshould not be construed or interpreted as limiting the scope of theinvention.

[0021] Silicon Carbide Layers

[0022] The silicon and carbon containing layer may comprise a siliconcarbide dielectric layer or a doped silicon carbide layer. The siliconcarbide layer may be a barrier layer disposed adjacent a conductivematerial or dielectric layer or may be an etch stop deposited betweenone or more dielectric layers.

[0023] The silicon carbide layer or oxygen doped silicon carbide layeris deposited by reacting an organosilicon compound and, optionally oneor more dopants, to form a dielectric layer comprising carbon-siliconbonds and a dielectric constant less than about 4. The silicon andcarbon containing layer is preferably an amorphous hydrogenated siliconcarbide. The amorphous silicon carbide layer is produced by the reactionof an organosilane compound, or a carbon containing material and asilicon containing material, in a plasma of an inert gas.

[0024] The silicon carbide layer may also contain hydrogen, oxygen,nitrogen, or combinations thereof. An oxygen source, such as oxygen,ozone, or an oxygen containing organosilicon precursor, or a nitrogensource, such as ammonia, may be used during the reaction to form theoxygen doped and/or nitrogen doped silicon carbide layers. Oxygen dopedsilicon carbide generally includes less than about 15 atomic percent(atomic %) of oxygen or less, preferably about 10 atomic % or less ofoxygen. Nitrogen doped silicon carbide may comprise up to 20 atomic % ofnitrogen.

[0025] Suitable organosilane compounds include aliphatic organosiliconcompounds, cyclic organosilicon compounds, or combinations thereof.Cyclic organosilicon compounds typically have a ring comprising three ormore silicon atoms and the ring may further comprise one or more oxygenatoms. Commercially available cyclic organosilicon compounds includerings having alternating silicon and oxygen atoms with one or two alkylgroups bonded to the silicon atoms.

[0026] Aliphatic organosilicon compounds have linear or branchedstructures comprising one or more silicon atoms and one or more carbonatoms, and the structure may further comprise oxygen. Commerciallyavailable aliphatic organosilicon compounds include organosilanes thatdo not contain oxygen between silicon atoms, and organosiloxanes thatcontain oxygen between two or more silicon atoms.

[0027] Organosilicon compounds contain carbon atoms in organic groups.Low dielectric constant layers are prepared from organosilicon compoundsthat have one or more carbon atoms attached to silicon wherein thecarbon is not readily removed by oxidation at suitable processingconditions. Organic groups may include alkyl, alkenyl, cyclohexenyl, andaryl groups in addition to functional derivatives thereof.

[0028] Cyclic organosilicon compounds include, for example, one or moreof the following compounds:

[0029] 1,3,5-trisilano-2,4,6-trimethylene, —(—SiH₂CH₂—)₃— (cyclic)

[0030] 2,4,6,8-tetramethylcyclotetrasiloxane (TMCTS) —(—SiHCH₃—O—)₄—(cyclic)

[0031] octamethylcyclotetrasiloxane (OMCTS), —(—Si(CH₃)₂—O—)₄— (cyclic)

[0032] 2,4,6,8,10-pentamethylcyclopentasiloxane, —(—SiHCH₃—O—)₅—(cyclic)

[0033] 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene,—(—SiH₂—CH₂—SiH₂—O—)₂— (cyclic)

[0034] hexamethylcyclotrisiloxane —(—Si(CH₃)₂—O—)₃— (cyclic)

[0035] Aliphatic organosilicon compounds include, for example, one ormore of the following compounds:

[0036] methylsilane, CH₃—SiH₃

[0037] dimethylsilane, (CH₃)₂—SiH₂

[0038] trimethylsilane, (CH₃)₃—SiH

[0039] dimethyldimethoxysilane, (CH₃)₂—Si—(OCH₃)₂

[0040] ethylsilane, CH₃—CH₂—SiH₃

[0041] disilanomethane, SiH₃—CH₂—SiH₃

[0042] bis(methylsilano)methane, CH₃—SiH₂—CH₂—SiH₂—CH₃

[0043] 1,2-disilanoethane, SiH₃—CH₂—CH₂—SiH₃

[0044] 1,2-bis(methylsilano)ethane, CH₃—SiH₂—CH₂—CH₂—SiH₂—CH₃

[0045] 2,2-disilanopropane, SiH₃—C(CH₃)₂—SiH₃

[0046] 1,3-dimethyldisiloxane, CH₃—SiH₂—O—SiH₂—CH₃

[0047] 1,1,3,3-tetramethyldisiloxane, (CH₃)₂—SiH—O—SiH—(CH₃)₂

[0048] hexamethyldisiloxane (HMDS), (CH₃)₃—Si—O—Si—(CH₃)₃

[0049] 1,3-bis(silanomethylene)disiloxane, (SiH₃—CH₂—SiH₂—)₂—O

[0050] bis(1-methyldisiloxanyl)methane, (CH₃—SiH₂—O—SiH₂—)₂—CH₂

[0051] 2,2-bis(1-methyldisiloxanyl)propane, (CH₃—SiH₂—O—SiH₂—)₂—C(CH₃)2, and

[0052] hexamethoxydisiloxane (HMDOS) (CH₃O)₃—Si—O—Si—(OCH₃)_(3.)

[0053] The above list is illustrative and should not be construed orinterpreted as limiting the scope of the invention.

[0054] Generally, the organosilicon compounds are reacted in a plasmacomprising a relatively inert gas, such as nitrogen (N₂), and preferablya noble gas such as helium or argon. The deposited silicon carbidelayers have dielectric constants of about 5 or less, and the dopedsilicon carbide layers may have dielectric constants of about 3 or less.

[0055] A preferred silicon carbide layer is deposited in one embodimentby supplying trimethylsilane to a plasma processing chamber at a flowrate between about 10 and about 5000 standard cubic centimeters perminute (sccm). An inert gas, such as helium, argon, or combinationsthereof, is also supplied to the chamber at a flow rate between about 50sccm and about 5000 sccm. The chamber pressure is maintained betweenabout 100 milliTorr and about 15 Torr. The substrate surface temperatureis maintained between about 100° C. and about 450° C. during thedeposition process.

[0056] Alternatively, a doped silicon carbide layer can be deposited byintroducing an oxygen source and/or a nitrogen source, or other dopant,into the processing chamber at a flow rate between about 50 sccm andabout 10,000 sccm. For example, a nitrogen containing or nitrogen dopedsilicon carbide layer may be deposited by introducing a nitrogen source,such as ammonia, nitrogen, a mixture of nitrogen and hydrogen, orcombinations thereof, during deposition. An example process fordepositing a nitrogen containing silicon carbide layer is disclosed inU.S. patent application Ser. No. 09/793,818, filed on Feb. 23, 2001,which is incorporated by reference to the extent not inconsistent withthe claims and disclosure described herein. An example process fordepositing an oxygen containing silicon carbide layer is disclosed inU.S. patent application Ser. No. 10/196,498, filed on Jul. 15, 2002,which is incorporated by reference to the extent not inconsistent withthe claims and disclosure described herein.

[0057] The organosilicon compound, inert gas, and optional dopant, areintroduced to the processing chamber via a gas distribution plate spacedbetween about 200 millimeters (mm) and about 600 millimeters from thesubstrate on which the silicon carbide layer is being deposited. Powermay be applied for a single or dual frequency RF power source. Forexample, power from a single 13.56 MHz RF power source is supplied tothe chamber 10 to form the plasma at a power density between about 0.3watts/cm² and about 3.2 watts/cm², or a power level between about 100watts and about 1000 watts for a 200 mm substrate. A power densitybetween about 0.9 watts/cm² and about 2.3 watts/cm², or a power levelbetween about 300 watts and about 700 watts for a 200 mm substrate, ispreferably supplied to the processing chamber to generate the plasma.

[0058] Additionally, the ratio of the silicon source to the dopant inthe gas mixture should have a range between about 1:1 and about 100:1.The above process parameters provide a deposition rate for the siliconcarbide layer in a range between about 100 Å/min and about 3000 Å/minwhen implemented on a 200 mm (millimeter) substrate in a depositionchamber available from Applied Materials, Inc., located in Santa Clara,Calif.

[0059] The embodiments described herein for depositing silicon carbidelayers are provided to illustrate the invention, the particularembodiment shown should not be used to limit the scope of the invention.The invention also contemplates other processes and materials used todeposit silicon carbide layers.

[0060] Silicon Oxycarbide Layers

[0061] The silicon oxycarbide layer generally comprises between about 15atomic % or greater of oxygen in the layer. The silicon oxycarbide layermay also contain hydrogen, nitrogen, or combinations thereof.

[0062] A preferred silicon oxycarbide layer comprises silicon-oxygenbonds and silicon-carbon bonds that contribute to low dielectricconstants and barrier properties. The carbon content of the depositedlayer is between about 5 and about 30 atomic % excluding hydrogen atoms,and is preferably between about 10 and about 20 atomic % excludinghydrogen atoms. The deposited layers may contain C—H or C—F bondsthroughout to provide hydrophobic properties to the silicon oxycarbidelayer.

[0063] The silicon oxycarbide layers are produced from organosiliconcompounds containing carbon in organo groups that are not readilyremoved by oxidation at processing conditions. Suitable organosiliconcompounds are described above and include aliphatic organosiliconcompounds, cyclic organosilicon compounds, or combinations thereof. Forexample, suitable organo groups include alkyl, alkenyl, cyclohexenyl,and aryl groups and functional derivatives.

[0064] In a preferred aspect of the invention, the silicon oxycarbidelayer is deposited by reacting an organosilicon compound comprisingthree or more alkyl groups with an oxidizing gas comprising ozone. Thesilicon oxycarbide layer may be deposited without an oxidizer if theorganosilicon compound includes oxygen. The preferred organosiliconcompounds include, for example:

[0065] trimethylsilane, (CH₃)₃—SiH

[0066] tetramethylsilane, (CH₃)₄—Si

[0067] 1,1,3,3-tetramethyldisiloxane, (CH₃)₂—SiH—O—SiH—(CH₃)₂

[0068] hexamethyldisiloxane, (CH₃)₃—Si—O—Si—(CH₃)₃

[0069] 2,2-bis(1-methyldisiloxanyl)propane, (CH₃—SiH₂—O—SiH₂—)₂—C(CH₃)₂

[0070] 1,3,5,7-tetramethylcyolotetrasiloxane, —(—SiHCH₃—O—)₄— (cyclic)

[0071] octamethylcyclotetrasiloxane, —(—Si(CH₃)₂—O—)₄— (cyclic)

[0072] 1,3,5,7,9-pentamethylcyclopentasiloxane, —(—SiHCH₃—O—)₅— (cyclic)

[0073] and fluorinated derivatives thereof.

[0074] The organosilicon compounds are oxidized during deposition of thesilicon oxycarbide layer, preferably by reaction with oxygen (O₂), ozone(O₃), nitrous oxide (N₂O), carbon monoxide (CO), carbon dioxide (CO₂),water (H₂O), or combinations thereof. When ozone is used as an oxidizinggas, an ozone generator typically converts about 15 wt. % of the oxygenin a source gas to ozone, with the remainder typically being oxygen.However, the ozone concentration may be increased or decreased basedupon the amount of ozone desired and the type of ozone generatingequipment used. Organosilicon compounds that contain oxygen may bedisassociated to provide the oxygen. During deposition of the siliconoxycarbide layer, the substrate is maintained at a temperature betweenabout −20° C. and about 500° C., and preferably is maintained at atemperature between about 170° C. and about 180° C.

[0075] For a plasma enhanced deposition of the silicon oxycarbide layer,the organosilicon material is deposited using a power density rangingbetween about 0.03 W/cm² and about 6.4 W/cm², which is a RF power levelof between about 10 W and about 2000 W for a 200 mm substrate.Preferably, the RF power level is between about 300 W and about 1700 W.The RF power is provided at a frequency between about 0.01 MHz and 300MHz. The RF power may be provided continuously or in short durationcycles wherein the power is on at the stated levels for cycles less thanabout 200 Hz, and the on cycles total between about 10% and about 50% ofthe total duty cycle. The deposition process of the low dielectricconstant layer is performed in a substrate processing system describedin more detail below. The silicon oxycarbide layer can be depositedcontinuously or with interruptions, such as changing chambers orproviding cooling time, to improve porosity.

[0076] In one aspect, a cyclic organosilicon compound and an aliphaticorganosilicon compound are reacted with an oxidizing gas in amountssufficient to deposit a low dielectric constant layer on a semiconductorsubstrate, wherein the cyclic organosilicon compound comprises at leastone silicon-carbon bond. The aliphatic organosilicon compound contains asilicon-hydrogen bond or a silicon-oxygen bond, preferably asilicon-hydrogen bond. For example, the cyclic organosilicon compoundmay be 1,3,5,7-tetramethylcyclotetrasiloxane oroctamethylcyclotetrasiloxane and the aliphatic organosilicon compoundmay be trimethylsilane or 1,1,3,3-tetramethyldisiloxane.

[0077] In another aspect, both the cyclic organosilicon compound and thealiphatic organosilicon compound contain a silicon-hydrogen bond. Forexample, 1,3,5,7-tetramethylcyclotetrasiloxane and trimethylsilane or1,1,3,3-tetramethyldisiloxane are blended and oxidized while applying RFpower.

[0078] In one embodiment of plasma enhanced deposition, oxygen or oxygencontaining compounds are dissociated to increase reactivity and toachieve desired oxidation of the deposited layer. RF power is coupled tothe deposition chamber to increase dissociation of the compounds. Thecompounds may also be dissociated in a microwave chamber prior toentering the deposition chamber.

[0079] Although deposition preferably occurs in a single depositionchamber, the silicon oxycarbide layer can be deposited sequentially intwo or more deposition chambers, e.g., to permit cooling of the layerduring deposition. Additionally, the silicon oxycarbide and siliconcarbide layers may be deposited in situ in the same chamber anddeposited subsequently by using selective precursors and controlling theprocessing parameters and the composition of processing gases. Forexample, both the silicon carbide an silicon oxycarbide layer may bedeposited using trimethylsilane with ammonia being used in the siliconcarbide deposition to form a nitrogen doped silicon carbide, andsubsequently using ozone during deposition of the silicon oxycarbidematerial.

[0080] Termination and Initiation Layers

[0081] In one aspect, interlayer adhesion may be improved by depositinga termination layer on the silicon carbide layer or a dielectricinitiation layer prior to depositing the silicon oxycarbide layer.

[0082] A termination layer may be deposited on the silicon carbide layerin order to improve subsequent deposition of dielectric materials. Thetermination layer may be deposited in situ by increasing the oxygenconcentration of the silicon carbide process gas to form a doped siliconcarbide layer or a doped silicon carbide layer with increased oxygencontent compared to a prior layer. The oxygen concentration may beincreased by using an oxidizing gas, an oxygen-containing organosiliconprecursor, or both, and may be used in greater amounts than the initialsilicon carbon layer if that layer is also an oxygen doped siliconcarbide layer. For example, the oxygen content of the oxygen dopedsilicon carbide layer may be between about 3 atomic percent (atomic %)and about 10 atomic %. The increased oxygen concentration is believed toremove carbon content from the deposited film as well as to densify thesilicon carbide surface to improve interlayer adhesion. The terminationlayer may be deposited at a thickness between about 100 Å and about 1000Å.

[0083] A dielectric initiation layer may be deposited on the siliconcarbide layer to seed the deposition of a silicon oxycarbide layer. Thedielectric initiation layer is deposited with a carbon-containingoxidizing compound and a nitrating compound used with an organosiliconprecursor instead of an oxidizing agent to deposit the layer atprocessing conditions approximately or equivalent to the siliconoxycarbide deposition. The carbon-containing oxidizing compound mayinclude carbon dioxide, carbon monoxide, and combinations thereof. Thenitrogen-containing compound may include ammonia, ammonia derivatives,hydrazine, a mixture of hydrogen and nitrogen, and combinations thereof.The dielectric initiation layer and silicon oxycarbide layer may bedeposited in situ by modifying the oxidizing gas and terminating orreducing the flow of nitrogen-containing compound. It was unexpectedlydiscovered that the use of both a carbon-containing oxidizing compoundand a nitrating compound significantly improved adhesion compared tousing just one of the components in forming a dielectric initiationlayer.

[0084] An example of a deposition of dielectric initiation layer in oneembodiment is as follows. A processing gas of a carbon-containingoxidizing compound and a nitrating compound, and an organosiliconprecursor organosilicon is supplied to the processing chamber.Organosilicon compounds, such as trimethylsilane and/or1,3,5,7-tetramethylcyclotetrasiloxane, are supplied to a plasmaprocessing chamber at a flow rate between about 100 milligrams/minute(mgm) and about 5000 mgm, respectively, a carbon-containing oxidizingcompound is supplied at a flow rate between about 10 sccm and about 2000sccm, a nitrating compound is supplied at a flow rate between about 10sccm and about 2000 sccm, and optionally, supplying a noble gas at aflow rate between about 1 sccm and about 10000 sccm. The chamber ismaintained at a substrate temperature between about 0° C. and about 500°C. and a chamber pressure is maintained between about 100 milliTorr andabout 100 Torr with an applied RF power of between about 0.03 watts/cm²and about 1500 watts/cm². The processing gas may be introduced into thechamber by a gas distributor, the gas distributor may be positionedbetween about 200 mils and about 700 mils from the substrate surface.

[0085] The RF power can be provided at a high frequency such as between13 MHz and 14 MHz or a mixed frequency of the high frequency and the lowfrequency. For example, a high frequency of about 13.56 MHz may be usedas well as a mixed frequency with a high frequency of about 13.56 MHzand low a frequency of about 356 KHz. The RF power can be providedcontinuously or in short duration cycles wherein the power is on at thestated levels for cycles less than about 200 Hz, and the on cycles totalbetween about 10% and about 30% of the total duty cycle. Additionally, alow frequency RF power may be applied during the deposition process. Forexample, an application of less than about 300 watts, such as less thanabout 100 watts at between about 100 KHz and about 1 MHz, such as 356KHz may be used to modify film properties, such as increasing thecompressive stress of a SiC film to reduce copper stress migration.

[0086] An increased amount of inert gas used for depositing thetermination layer compared to the silicon carbide layer, and anincreased amount of inert gas in the dielectric initiation layercompared to the silicon oxycarbide layer was also observed to improveinterlayer adhesion.

[0087] Deposition Concurrent Treatments to Improve Interlayer Adhesion

[0088] It is believed that reducing the carbon content at the interfacebetween the silicon carbide layers and silicon oxycarbide layersimproves interlayer adhesion. Modification of processing variablesduring deposition is believed to affect carbon content and thusadhesion.

[0089] For example, in another aspect, a dielectric initiation layer maybe deposited with an organosilicon compound and an oxidizing compound,by the modification of one or more processing variables. Decreasingspacer heating and increasing deposition temperatures during dielectricinitiation layer deposition were also observed to result in improvingadhesion with silicon carbide layers. Additionally, decreasingorganosilicon precursor flow rates during dielectric initiation layerdeposition was observed to result in increasing adhesion with siliconcarbide materials. Furthermore, depositing a dielectric initiation layerof silicon oxycarbide at increasing deposition rates compared to thesubsequently deposited silicon oxycarbide layer has been observed toincrease adhesion with silicon carbide layers.

[0090] Also, It has been observed that dual frequency RF power sourcesused for the deposition of the dielectric initiation layer will improveadhesion compared to single frequency RF power sources and/orapplications, assuming all other processing parameters are constant.

[0091] Post-Deposition Treatments to Improve Interlayer Adhesion

[0092] Following deposition, each deposited dielectric material may beannealed at a temperature between about 100° C. and about 400° C. forbetween about 1 minute and about 60 minutes, preferably at about 30minutes, to reduce the moisture content and increase the solidity andhardness of the dielectric material, if desired. The anneal ispreferably performed after the deposition of the next layer whichprevents shrinkage or deformation of the dielectric layer. Inert gases,such as argon and helium, may be added to the annealing atmosphere.

[0093] The deposited silicon oxycarbide layer or silicon carbide layermay also be plasma treated prior to deposition of resist materialthereon. The plasma treatment is believed to remove a portion of thecarbon material from the surface of the silicon oxycarbide layer orsilicon carbide layer that reduces the surface's reactivity tosubsequently deposited materials. The plasma treatment may be performedin the same chamber used to deposit the silicon and carbon containingmaterial.

[0094] The plasma treatment generally includes providing an inert gasincluding helium, argon, neon, xenon, krypton, or combinations thereof,to a processing chamber at a flow rate between about 500 sccm and about3000 sccm, and generating a plasma in the processing chamber.Optionally, an oxidizing gas, such as oxygen, may be used with orinstead of the inert gas in a post-deposition treatment process. Theplasma may be generated using a power density ranging between about 0.03W/cm² and about 3.2 W/cm², which is a RF power level of between about 10W and about 1000 W for a 200 mm substrate. Preferably, a power level ofbetween about 200 watts and about 800 watts is used in depositing thesilicon carbide material for a 200 mm substrate. The RF power can beprovided at a high frequency such as between 13 MHz and 14 MHz. The RFpower can be provided continuously or in short duration cycles whereinthe power is on at the stated levels for cycles less than about 200 Hz,and the on cycles total between about 10% and about 30% of the totalduty cycle.

[0095] The processing chamber is generally maintained at a chamberpressure of between about 3 Torr and about 12 Torr. A chamber pressurebetween about 7 Torr and about 10 Torr. The substrate is maintained at atemperature between about 300° C. and about 450° C. during the plasmatreatment. A substrate temperature between about 350° C. and about 400°C. may be used during the plasma treatment. The plasma treatment may beperformed between about 3 seconds and about 120 seconds, with a plasmatreatment between about 5 seconds and about 40 seconds preferably used.The processing gases may be introduced into the processing chamberthrough a gas distributor, or “showerhead” that may be positionedbetween about 200 mils and about 1000 mils, for example between 300 milsand 500 mils from the substrate surface. Showerhead positioning betweenabout 300 mils and about 400 mils from the substrate during the plasmatreatment has been observed to produce effective plasma treatment by theprocessing gases on the substrate surface.

[0096] However, it should be noted that the respective parameters may bemodified to perform the plasma processes in various chambers and fordifferent substrate sizes, such as 300 mm substrates. An example of aplasma treatment for a silicon and carbon containing film is furtherdisclosed in U.S. patent application Ser. No. 09/336,525, entitled,“Plasma Treatment to Enhance Adhesion and to Minimize Oxidation ofCarbon-Containing Layers,” filed on Jun. 18, 1999, which is incorporatedby reference to the extent not inconsistent with the disclosure andclaimed aspects of the invention described herein.

[0097] E-Beam Treatment

[0098] In another aspect of the invention, deposited silicon carbidelayers and silicon oxycarbide layers may be cured by an electronic beam(e-beam) technique to improve interlayer adhesion. The e-beam treatmentmay be performed in situ within the same processing system, for example,transferred from one chamber to another without break in a vacuum. Whilethe best results for adhesion has been observed by e-beam treatment ofstacks of the silicon carbide layers and silicon oxycarbide layers,individual silicon carbide layers and silicon oxycarbide layers may betreated to improve adhesion to adjacent layers.

[0099] An e-beam treatment of a silicon carbide layer may comprise theapplication or exposure to a dosage between about 50 micro coulombs persquare centimeter (μC/cm²) and about 1600 μC/cm², for example, about 800μC/cm², at energy ranges between about 0.5 kiloelectron volts (KeV) andabout 30 KeV, for example between about 4 KeV and about 10 KeV, such as8 KeV. Dosages may vary on the size of the substrate being treated, forexample, a dosage between about 50 μC/cm² and about 1600 μC/cm² has beenobserved to result in adhesion of layers formed on 300 mm substrates anda dosage between about 200 μC/cm² and about 800 μC/cm² has been observedto result in adhesion of layers formed on 200 mm substrates

[0100] The electron beams are generally generated at a pressure of about1 mtorr to about 100 mTorr. An gas ambient including an inert gas,including nitrogen, helium, argon, xenon, an oxidizing gas includingoxygen, a reducing gas including hydrogen, a blend of hydrogen andnitrogen, ammonia, or any combination of these gases. The electron beamcurrent ranges from about 1 mA to about 40 mA, and more preferably fromabout 2 mA to about 20 mA. The electron beam may cover an area fromabout 4 square inches to about 700 square inches. The e-beam processapparatus 200 operates ranges from about −200 degrees Celsius to about600 degrees Celsius, e.g., about 400 degrees Celsius.

[0101] Although any e-beam device may be used, one exemplary device isthe EBK chamber, available from Applied Materials, Inc., of Santa ClaraCalif. E-beam processing is more fully described in U.S. patentapplication Ser. No. 10/302,375 (AMAT 7625), entitled, “Method ForCuring Low Dielectric Constant Film By Electron Beam”, filed on Nov. 22,2002, and incorporated by reference to the extent not inconsistent withthe claims aspects and disclosure herein.

[0102] Deposition of a Dual Damascene Structure

[0103] A damascene structure that is formed using the plasma treatmentdescribed herein for a silicon oxycarbide layer disposed on a siliconcarbide layer is shown in FIG. 1.

[0104] While the following interlayer adhesion processes describedherein used between a low k etch stop layer 114 and an interlayerdielectric layer 118, the invention contemplates that the interlayeradhesion processes may be used between any suitable dielectric layers ina damascene structure, such as between silicon carbide barrier layer 112and dielectric layer 110. Alternatively, while not shown, the inventioncontemplates that the adhesion improving layer and techniques describedherein may be used to improve adhesion between a silicon oxycarbidelayer and a silicon carbide layer deposited on top of the siliconoxycarbide layer, for example between layers 110 and 114.

[0105] A silicon oxycarbide material is deposited from an oxidizedorganosilicon compound by the process described herein, as an interlayerdielectric material, such as the first dielectric layer 110. A firstsilicon carbide barrier layer 112 is generally deposited on thesubstrate surface to eliminate inter-level diffusion between thesubstrate and subsequently deposited material. The first silicon carbidebarrier layer 112 may be nitrogen and/or oxygen doped. A capping layerof nitrogen free silicon carbide (not shown) may be deposited in situ onthe first silicon carbide barrier layer 112 by minimizing or eliminatingthe nitrogen source gas.

[0106] The first dielectric layer 110 of the oxidized organosiliconcompound is deposited on a first silicon carbide barrier layer 112 onthe substrate surface. The first dielectric layer 110 may then be plasmatreated or e-beam treated according to the processes described herein.Alternatively, a silicon oxide cap layer (not shown) may be deposited insitu on the first dielectric layer 110 by increasing the oxygenconcentration in the silicon oxycarbide deposition process describedherein to remove carbon from the deposited material.

[0107] An etch stop (or second barrier layer) 114 of a silicon carbide,which may be doped with nitrogen or oxygen, is then deposited on thefirst dielectric layer 110. The etch stop 114 may have a nitrogen freesilicon carbide capping layer deposited thereon. The etch stop 114 isthen pattern etched to define the openings of the contacts/vias 116. Aninterlayer adhesion layer or surface 115 may be formed on the layer 114prior to subsequent processing, such as etching or additional dielectricetching, to improve interlayer adhesion with subsequently depositeddielectric materials. The improved adhesion layer may comprise thedielectric initiation layer or the silicon carbide termination layer asdescribed herein. The interlayer adhesion surface may be formed by thetechniques described herein. A second dielectric layer 118 of anoxidized organosilane or organosiloxane is then deposited over thepatterned etch stop.

[0108] The second dielectric layer 118 is then plasma treated accordingto the process described herein or has a silicon oxide cap materialdisposed thereon by the process described herein. A resist,conventionally known in the art, such as photoresist material UV-5,commercially available from Shipley Company Inc., of Marlborough, Mass.,is then deposited and patterned by conventional means known in the artto define the interconnect lines 120. A single etch process is thenperformed to define the interconnect down to the etch stop and to etchthe unprotected dielectric exposed by the patterned etch stop to definethe contacts/vias.

[0109] A preferred dual damascene structure fabricated in accordancewith the invention includes the plasma treatment or e-beam treatment ofan exposed silicon oxycarbide layer as shown in FIG. 2E, and the methodof making the structure is sequentially depicted schematically in FIGS.2A-2H, which are cross-sectional views of a substrate having the stepsof the invention formed thereon.

[0110] As shown in FIG. 2A, a first silicon carbide barrier layer 112 isdeposited on the substrate surface. The silicon carbide material of thefirst silicon carbide barrier layer 112 may be doped with nitrogenand/or oxygen. While not shown, a capping layer of nitrogen free siliconcarbide or silicon oxide may be deposited on the barrier layer 112. Thenitrogen free silicon carbide or silicon oxide may be deposited in situby adjusting the composition of the processing gas. The first siliconcarbide barrier layer 112 may be plasma treated with an inert gas.Helium (He), argon (Ar), neon (Ne), and combinations thereof, may beused for the inert gas. The plasma treatment may be performed in situwith the deposition of the silicon carbide barrier layer 112.

[0111] In general, the following process parameters can be used toplasma treat the first silicon carbide barrier layer 112. The processparameters range from a chamber pressure of about 1 Torr to about 10Torr, an inert gas flow rate of about 1000 sccm to about 7000 sccm, anda radio frequency (RF) power of about 1 watt/cm² to about 10 watts/cm².The silicon carbide layer barrier layer 112 is plasma treated for lessthan about 120 seconds.

[0112] An initial first dielectric layer 110 of silicon oxycarbide froman oxidized organosilane or organosiloxane by the process describedherein, such as trimethylsilane, is deposited on the first siliconcarbide barrier layer 112 to a thickness of about 5,000 to about 15,000Å, depending on the size of the structure to be fabricated. The firstdielectric layer may also comprise other low k dielectric material suchas a low polymer material including paralyne or a low k spin-on glasssuch as un-doped silicon glass (USG) or fluorine-doped silicon glass(FSG). The first dielectric layer may then be treated by a plasmaprocess as described herein.

[0113] As shown in FIG. 2B, the low k etch stop 114, which may benitrogen and/or oxygen doped silicon carbide, is then deposited on thefirst dielectric layer to a thickness of about 100 Å to about 1000 Å. Aninterlayer dielectric adhesion layer or surface 115 formed by one of theprocesses described herein, such as a dielectric initiation layer, isthen formed or deposited on the low k etch stop layer 114. The low ketch stop 114 and/or interlayer dielectric adhesion layer or surface 115may be plasma treated as described herein for the silicon carbidematerials or silicon oxycarbide materials.

[0114] The low k etch stop 114 is then pattern etched to define thecontact/via openings 116 and to expose first dielectric layer 110 in theareas where the contacts/vias are to be formed as shown in FIG. 2C.Preferably, the low k etch stop 114 is pattern etched using conventionalphotolithography and etch processes using fluorine, carbon, and oxygenions. While not shown, a nitrogen-free silicon carbide or silicon oxidecap layer between about 100 Å to about 500 Å may be deposited on the lowk etch stop 114 and/or interlayer dielectric adhesion layer or surface115 prior to depositing further materials.

[0115] After low k etch stop 114 has been etched to pattern thecontacts/vias and the resist material has been removed, a seconddielectric layer 118 of silicon oxycarbide from an oxidized organosilaneor organosiloxane by the process described herein, such astrimethylsilane, is deposited to a thickness of about 5,000 to about15,000 Å as shown in FIG. 2D. The second dielectric layer 118 is thenplasma treated with helium as described herein for first dielectriclayer 110.

[0116] A resist material 122 is then deposited on the second dielectriclayer 118 (or cap layer) and patterned preferably using conventionalphotolithography processes to define the interconnect lines 120 as shownin FIG. 2E. The resist material 122 comprises a material conventionallyknown in the art, preferably a high activation energy resist material,such as UV-5, commercially available from Shipley Company Inc., ofMarlborough, Mass. The interconnects and contacts/vias are then etchedusing reactive ion etching or other anisotropic etching techniques todefine the metallization structure (i.e., the interconnect andcontact/via) as shown in FIG. 2F. Any resist material or other materialused to pattern the etch stop 114 or the second dielectric layer 118 isremoved using an oxygen strip or other suitable process.

[0117] The metallization structure is then formed with a conductivematerial such as aluminum, copper, tungsten or combinations thereof.Presently, the trend is to use copper to form the smaller features dueto the low resistivity of copper (1.7 mW-cm compared to 3.1 mW-cm foraluminum). Preferably, as shown in FIG. 2G, a suitable barrier layer124, such as tantalum nitride, is first deposited conformally in themetallization pattern to prevent copper migration into the surroundingsilicon and/or dielectric material. Thereafter, copper 126 is depositedusing either chemical vapor deposition, physical vapor deposition,electroplating, or combinations thereof to form the conductivestructure. Once the structure has been filled with copper or othermetal, the surface is planarized using chemical mechanical polishing, asshown in FIG. 2H.

EXAMPLES

[0118] The following examples demonstrate various embodiments of theadhesion processes described herein as compared to a standard interlayerstack to illustrate the improved interlayer adhesion. These exampleswere undertaken using a chemical vapor deposition chamber, and in aCentura DxZ™ or Producer™ system which includes a solid-state RFmatching unit with a two-piece quartz process kit, both fabricated andsold by Applied Materials, Inc., Santa Clara, Calif.

[0119] Base Interlayer Stack and Adhesion Test

[0120] Test samples were prepared as follows. A stack of dielectriclayers were deposited on a silicon substrate as follows: a first layerof silicon carbide as described herein was deposited to about 1000 Åthick on the silicon substrate, about 5000 Å of a silicon oxycarbidedielectric layer as described herein was deposited on the first siliconcarbide layer, and a second layer of silicon carbide as described hereinwas deposited to about 1000 Å thick on the silicon oxycarbide layer.

[0121] The silicon carbide layers were deposited by introducingtrimethylsilane (TMS) at a flow rate of 160 sccm, helium at a flow rateof 400 sccm, and ammonia at a flow rate of 325 sccm into a processingchamber being operated at a temperature of 350° C., a pressure of 3Torr, and a RF power of 300 watts with a heater spacing of about 300mils between the heater and a substrate, to deposit the material.

[0122] The silicon oxycarbide layer was deposited by introducingtrimethylsilane (TMS) at a flow rate of 1400 sccm, helium at a flow rateof 400 sccm, and oxygen at a flow rate of 400 sccm into a processingchamber being operated at a temperature of 350° C., a pressure of 5Torr, and a RF power of 700 watts with a heater spacing of about 360mils between the heater and a substrate, to deposit the material.

[0123] Adhesion testing was performed on the test samples as follows.Between about 120 μm and about 150 μm of epoxy material with knowdelamination characteristics were deposited on the test samples. Thetest samples were then baked or cured for one hour at approximately 190°C. and then cleaved into 1 cm by 1 cm samples and cooled to −170° C.with liquid nitrogen. The samples were then observed to determinedelamination, which occurs at a weakest interlayer interface at a giventemperature. The shrinkage of the epoxy at a given temperaturecorrelates to the forces that are required to induce peeling. From thisobservation, a determination of adhesion can be calculated. Adhesion(kic) is based on the formula σ{square root}(h/2), with h being theepoxy thickness and being the residual stress. The measured adhesion(kic) of an untreated or unmodified stack described above was about 0.22Mpa-m^(1/2).

[0124] Examples of the above processes and the corresponding adhesionvalues are as follows.

[0125] RF Frequency

[0126] Single and dual frequency deposition of a dielectric initiationlayers were prepared as follows. Single frequency dielectric initiationlayer was deposited by introducing trimethylsilane (TMS) at a flow rateof 600 sccm, helium at a flow rate of 1200 sccm, oxygen at a flow rateof 1000 sccm, acetylene (C₂H₄) at a flow rate of 1000 sccm, and OMCTS ata flow rate of 4000 mgm, into a processing chamber being operated at atemperature of 400° C., a pressure of 3.5 Torr, and a RF power of 1100watts high frequency RF power, with a heater spacing of about 350 milsbetween the heater and a substrate to deposit the material.

[0127] The measured adhesion (kic) of the single frequency dielectricinitiation layer was observed to be about 0.3 Mpa-m^(1/2). Thedielectric constant was measured to be 3.28, the hardness of thedeposited layer was 2.68 GPa, and the layer modulus was measured to be17.3 GPa.

[0128] Dual frequency dielectric initiation layer was deposited byintroducing trimethylsilane (TMS) at a flow rate of 300 sccm, helium ata flow rate of 600 sccm, oxygen at a flow rate of 300 sccm, acetylene(C₂H₄) at a flow rate of 500 sccm, and OMCTS at a flow rate of 2000 mgm,into a processing chamber being operated at a temperature of 400° C., apressure of 4.5 Torr, and a RF power of 400 watts high frequency RFpower and 150 low frequency RF power, with a heater spacing of about 350mils between the heater and a substrate to deposit the material.

[0129] The measured adhesion (kic) of the dual frequency dielectricinitiation layer was observed to be about 0.29 Mpa-m^(1/2). Thedielectric constant was measured to be 2.96, the hardness of thedeposited layer was 2.03 GPa, and the layer modulus was measured to be12.27 GPa.

[0130] Generally, it has been observed that dual frequency layeradhesion is improved over single frequency layer adhesion. Further ithas also been observed that increasing power levels result in increasedadhesion. Additionally, increasing dielectric constants, hardness andmodulus can result in increased adhesion. In relation to the aboveexamples, the single frequency layer adhesion, 0.3 Mpa-m^(1/2), wasobserved to be greater than the dual frequency layer adhesion, 0.29Mpa-m^(1/2), however, the power level of the single frequency layer 1110W was greater than the dual frequency layer 400 W/150 W and thedielectric constant of the dual frequency layer adhesion, 2.96, wasimproved over the single frequency dielectric constant, 3.28. Under suchdielectric layer property trends, processes for depositing dielectriclayers may be modified to provide for desired dielectric layerproperties such as improved dielectric constant with reduced adhesion,or improved adhesion with less than optimal dielectric properties.

[0131] Doped Dielectric Initiation Layer

[0132] Comparison of dielectric initiation layer to improve interlayeradhesion with the addition of dopants. A carbon dioxide additive onlydielectric initiation layer was deposited by introducing trimethylsilane(TMS) at a flow rate of 1400 sccm, helium at a flow rate of 400 sccm,carbon dioxide at a flow rate of 400 sccm, into a processing chamberbeing operated at a temperature of 350° C., a pressure of 5 Torr, a RFpower of 700 watts, with a heater spacing of about 360 mils between theheater and a substrate to deposit the material. The measured adhesion(kic) was about 0.21 Mpa-m^(1/2).

[0133] An ammonia additive only dielectric initiation layer wasdeposited by introducing trimethylsilane (TMS) at a flow rate of 1400sccm, helium at a flow rate of 400 sccm, ammonia at a flow rate of 325sccm, into a processing chamber being operated at a temperature of 350°C., a pressure of 5 Torr, a RF power of 700 watts, with a heater spacingof about 360 mils between the heater and a substrate to deposit thematerial. The measured adhesion (kic) was about 0.26 Mpa-m^(1/2).

[0134] A carbon dioxide and ammonia additive dielectric initiation layerwas deposited by introducing trimethylsilane (TMS) at a flow rate of1400 sccm, helium at a flow rate of 400 sccm, carbon dioxide at a flowrate of 400 sccm, and ammonia at a flow rate of 325, into a processingchamber being operated at a temperature of 350° C., a pressure of 5Torr, a RF power of 700 watts, with a heater spacing of about 360 milsbetween the heater and a substrate to deposit the material. The measuredadhesion (kic) was about 0.28 Mpa-m^(1/2.)

[0135] Oxygen Doped Termination Layer

[0136] Oxygen doped termination layer to improve interlayer adhesiontest results and examples are as follows. An oxygen doped siliconcarbide termination layer was deposited by introducing trimethylsilane(TMS) at a flow rate of 160 sccm, helium at a flow rate of 400 sccm,oxygen at a flow rate of 400 sccm, into a processing chamber beingoperated at a temperature of 350° C., a pressure of 3 Torr, a RF powerof 300 watts, with a heater spacing of about 300 mils between the heaterand a substrate to deposit the material. The measured adhesion (kic) wasabout 0.27 Mpa-m^(1/2).

[0137] Modified Dielectric Initiation Layer and Termination Layers

[0138] Comparison of dielectric initiation layer test samples to improveinterlayer adhesion with regard to temperature, precursor flow andspacing are shown as follows. Two samples at temperatures of 350° C. and400° C. were deposited by introducing trimethylsilane (TMS) at a flowrate of 1400 sccm, helium at a flow rate of 400 sccm and oxygen at aflow rate of 400 sccm, into a processing chamber being operated at apressure of 5 Torr, a RF power of 700 watts, with a heater spacing ofabout 360 mils between the heater and a substrate to deposit thematerial. The measured adhesion (kic) was about 0.22 Mpa-m^(1/2) at 350°C. and about 0.27 Mpa-m^(1/2) at 400° C., indicating improved adhesionat increase deposition temperatures.

[0139] Three samples of TMS flow rates at 1400 sccm, 700 sccm, and 160sccm, were deposited by introducing helium at a flow rate of 400 sccmand oxygen at a flow rate of 400 sccm, into a processing chamber beingoperated at a temperature of 350° C., a pressure of 5 Torr, a RF powerof 700 watts, with a heater spacing of about 360 mils between the heaterand a substrate to deposit the material. The measured adhesion (kic) wasabout 0.22 Mpa-m^(1/2) at 1400 sccm, about 0.24 Mpa-m^(1/2) at 700 sccm,and about 0.28 Mpa-m^(1/2) at 160 sccm, indicating improved adhesion atreduced precursor flow rates.

[0140] Three samples of heater spacings of 300 mils, 360 mils, and 460mils, were deposited by introducing trimethylsilane (TMS) at a flow rateof 1400 sccm, helium at a flow rate of 400 sccm, and oxygen at a flowrate of 400 sccm, into a processing chamber being operated at atemperature of 350° C., a pressure of 5 Torr, a RF power of 700 watts todeposit the material. The measured adhesion (kic) was about 0.22Mpa-m^(1/2) at 360 mils, about 0.22 Mpa-m^(1/2) at 460 mils, and about0.30 Mpa-m^(1/2) at 300 mils, indicating improved adhesion by narrowerspacing between the heater and substrate surface.

[0141] While the foregoing is directed to preferred embodiments of thepresent invention, other and further embodiments of the invention may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims which follow.

What is claimed is:
 1. A method for processing a substrate, comprising:depositing a barrier layer on the substrate, wherein the barrier layercomprises silicon and carbon and has a dielectric constant less than 4;depositing a dielectric initiation layer adjacent the barrier layer; anddepositing a first dielectric layer adjacent the dielectric initiationlayer, wherein the dielectric layer comprises silicon, oxygen, andcarbon and has a dielectric constant of about 3 or less.
 2. The methodof claim 1, wherein the dielectric initiation layer is deposited byintroducing a processing gas comprising an organosilicon compound, acarbon-containing oxidizing compound, and a nitrating compound into aprocessing chamber, and reacting the processing gas to deposit thedielectric initiation layer.
 3. The method of claim 2, wherein thecarbon-containing oxidizing compound is selected from the group of anoxygen-containing organosilicon compound, carbon dioxide, carbonmonoxide, and combinations thereof.
 4. The method of claim 3, whereinthe organosilicon compound is selected from the group oftrimethylsilane, 2,4,6,8-tetramethylcyclotetrasiloxane,octamethylcyclotetrasiloxane, and combinations thereof.
 5. The method ofclaim 2, wherein the nitrogen-containing compound is selected from thegroup of ammonia, ammonia derivatives, hydrazine, a mixture of hydrogenand nitrogen, and combinations thereof.
 6. The method of claim 2,wherein the reacting processing gas comprises generating a plasma by asingle-frequency RF power source.
 7. The method of claim 2, wherein thereacting processing gas comprises generating a plasma by adual-frequency RF power source.
 8. The method of claim 2, wherein theprocessing gas further comprises an inert gas.
 9. The method of claim 1,further comprising treating the deposited dielectric initiation layer toan e-beam curing technique prior to subsequent processing.
 10. Themethod of claim 9, wherein the e-beam curing technique applied a dosageof 400 μC/cm² between about 6 kV and about 8 kV to the dielectricinitiation layer.
 11. The method of claim 1, wherein the dielectricinitiation layer comprises silicon, oxygen, and carbon, and is depositedat a first temperature, and wherein the first dielectric layer isdeposited at a second temperature less than the first temperature. 12.The method of claim 1, wherein the dielectric initiation layer isdeposited by introducing a first processing gas comprising anorganosilicon compound and an oxidizing compound into a processingchamber at a first organosilicon flow rate and reacting the firstprocessing gas, the first dielectric layer is deposited by introducing asecond processing gas comprising an organosilicon compound and anoxidizing compound into a processing chamber at a second organosiliconflow rate and reacting the second processing gas, wherein the secondorganosilicon flow rate is greater than the first organosilicon flowrate.
 13. The method of claim 1, wherein the dielectric initiation layercomprises silicon, oxygen, and carbon, and is deposited at a firstdeposition rate, and wherein the dielectric layer is deposited at asecond deposition rate less than the first deposition rate.
 14. A methodfor processing a substrate, comprising: depositing a first dielectriclayer on the substrate, wherein the first dielectric layer comprisessilicon and carbon and is deposited by a process comprising introducinga processing gas having an organosilicon compound and reacting theprocessing gas to deposit the first dielectric layer; reducing thecarbon content at a surface portion of the first dielectric layer; andthen depositing a second dielectric layer adjacent the first dielectriclayer, wherein the first dielectric layer comprises silicon, oxygen, andcarbon and has a dielectric constant of about 3 or less.
 15. The methodof claim 14, wherein the reducing of the carbon content at a surfaceportion of the first dielectric layer comprises forming an oxidizedsurface on the first dielectric layer.
 16. The method of claim 15,wherein the forming of the oxidized surface of the first dielectriclayer comprises exposing the first dielectric layer to a nitrogen-freeoxidizing plasma.
 17. The method of claim 15, wherein the forming of theoxidized surface of the first dielectric layer comprises introducing anoxygen-containing compound to the processing gas.
 18. The method ofclaim 14, wherein depositing the second dielectric layer comprisesintroducing a processing gas comprising an organosilicon compound and anoxidizing compound, and reacting the processing gas to deposit the firstdielectric layer, wherein the reducing of the carbon content at asurface portion of the first dielectric layer comprises introducing aprocessing gas comprising an organosilicon compound, a carbon-containingoxidizing compound, and a nitrating compound into a processing chamber,and reacting the processing gas to deposit a dielectric material at thesurface of the barrier layer
 19. The method of claim 14, furthercomprising treating the first dielectric layer to an e-beam curingtechnique prior to subsequent processing.
 20. A method for processing asubstrate, comprising: depositing a barrier layer on the substrate,wherein the barrier layer is deposited by introducing a processing gascomprising an organosilicon compound into a processing chamber andreacting the processing gas; depositing a barrier layer terminationlayer adjacent the barrier layer, wherein the barrier layer is depositedby introducing a processing gas comprising an organosilicon compound andan oxidizing compound into a processing chamber and reacting theprocessing gas; and depositing a first dielectric layer adjacent thebarrier layer termination layer, wherein the dielectric layer comprisessilicon, oxygen, and carbon and has a dielectric constant of about 3 orless.
 21. The method of claim 20, further comprising treating thebarrier layer termination layer to an e-beam curing technique, prior tosubsequent processing.
 22. The method of claim 21, wherein the e-beamcuring technique applied a dosage of 400 μC/cm² between about 6 kV andabout 8 kV to the dielectric initiation layer.
 23. The method of claim20, further comprising exposing the barrier layer termination layer to anitrogen-free oxidizing plasma prior to subsequent processing.